Long-term Survival of a Case of Rectal Neuroendocrine Carcinoma with Liver Metastasis

Colorectal neuroendocrine carcinoma（NEC）is extremely rare and has a dismal prognosis. However, no standardized treatment strategy has been established for this lesion. For patients with NEC and distant metastasis, disease stabilization is difficult even after treatment with multidisciplinary strategies including chemotherapy. Here we describe a case of rectal NEC that presented as multiple liver metastases; a favorable prognosis was obtained after treatment with a multidisciplinary strategy that included surgery, irradiation, and chemotherapy. A 66-year-old male presented with diarrhea and constipation. Colonoscopy and a computed tomography（CT）scan revealed a rectal mass involving all of the luminal circumference, after which a diagnosis of NEC was confirmed by pathological examination. A CT scan also revealed several liver metastases in S5, S6, and S8. Abdominoperineal resection with total mesenteric excision and lymphadenectomy, including the lateral area, was performed. After resection, we administered radiation for local disease control in the lateral area. We also administered chemotherapy consisting of cisplatin and irinotecan for the liver metastases because only the endocrine cell component constituted this tumor. After chemotherapy, a CT scan was performed to confirm that the liver metastasis in S5 and S6 had disappeared, and it was shown that the other lesion in S8 had shrunk substantially（it eventually disappeared）. Then, 48 months after resection, all metastatic liver tumors were under good control, and no other recurrent lesion was recognized. In conclusion, a multidisciplinary strategy including optimal chemotherapy seems to be important to achieve a favorable prognosis of NEC of the colorectum with distant metastasis.